Syntheses and structural investigation of some alkali metal ion-mediated LVVO2− (L2− = tridentate ONO ligands) species: DNA binding, photo-induced DNA cleavage and cytotoxic activities

Abstract

Eight alkali metal ion-mediated dioxidovanadium(v), [{V(V)O2L(1-6)}A(H2O)n]∝, complexes for A = Li(+), Na(+), K(+) and Cs(+), containing tridentate aroylhydrazonate ligands coordinating via ONO donor atoms, are described. All the synthesised ligands and the metal complexes were successfully characterised by elemental analysis, IR, UV-Vis and NMR spectroscopy. X-ray crystallographic investigation of 3, 5-7 shows the presence of distorted NO4 coordination geometries for LVO2(-) in each case, and varying μ-oxido and/or μ-aqua bridging with interesting variations correlated with the size of the alkali metal ions: with small Li(+), no bridging-O is found but four ion aggregates are found with Na(+), chains for K(+) and finally, layers for Cs(+). Two (5) or three-dimensional (3, 6 and 7) architectures are consolidated by hydrogen bonding. The dioxidovanadium(v) complexes were found to exhibit DNA binding activity due to their interaction with CT-DNA by the groove binding mode, with binding constants ranging from 10(3) to 10(4) M(-1). Complexes 1-8 were also tested for DNA nuclease activity against pUC19 plasmid DNA which showed that 6 and 7 had the best DNA binding and photonuclease activity; these results support their good protein binding and cleavage activity with binding constants ranging from 10(4) to 10(5) M(-1). Finally, the in vitro antiproliferative activity of all complexes was assayed against the HeLa cell line. Some of the complexes (2, 5, 6 and 7) show considerable activity compared to commonly used chemotherapeutic drugs. The variation in cytotoxicity of the complexes is influenced by the various functional groups attached to the aroylhydrazone derivative.

Study of DNA Interaction and Cytotoxicity Activity of Oxidovanadium(V) Complexes with ONO Donor Schiff Base Ligands

“…In addition, two additional new stretching bands appeared in the region 888 and 947 cm -1 assigned to the two ν(V=O) stretching of cis-ν(V=O) groups in 1 whereas for 2 it is observed in the region 891 and 975 cm -1 . These stretching vibrations are in agreement with the terminal V=O groups present in related oxidovanadium(V) complexes [43]. Additionally, a new stretching band observed at 819 cm −1 assigned to the ν(V−O−V) residue of complex 2 which further indicates the existence of a dinuclear species [45].…”

“…In continuation of our previous work on the synthesis, characterization, and biological studies of vanadium(V/IV) complexes [8,13,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], here we report a new mononuclear dioxidovanadium(V) (1) as well as an oxido-bridged dinuclear oxidovanadium(V) (2) complex, each with a tridentate ONO donor Schiff base ligand derived from 2,4-dihydroxybenzaldehyde and 2-amino-4-nitrophenol. Considering the therapeutic potential of the synthesized polyphenolic ligand molecule [27,30,46], corresponding oxidovanadium(V) complexes were synthesized to further investigate their pharmacological activities such as DNA interaction and anticancer activities.…”

Mercury based drug in ancient India: The red sulfide of mercury in nanoscale

“…The association of the rasasindur with BSA is directly correlated with the extent of fluorescence quenching [24]. Small molecules often bind to a set of sites in a protein molecule.…”

Supramolecular architecture and photophysical and biological properties of ruthenium(ii) polypyridyl complexes

“…[1,2,5]-Thiadiazolo-[3,4-f ]- [1,10]-phenanthroline (tdzp) was synthesized as per literature procedure in four steps. 37,38 The ruthenium(II) polypyridyl complexes of the type [Ru(N-N) 2 (tdzp)] 2+ (1-3) (where, NN = bpy, phen, dpq) were synthesized by refluxing a 1 : 1 molar ratio of cis-[Ru(NN) 2 Cl 2 ] and the [1,2,5]-thiadiazolo-[3,4-f ]- [1,10]-phenanthroline (tdzp) ligand in methanol water mixture (1 : 1). The complexes obtained were purified by column chromatography using an activated neutral alumina column and obtained as racemic mixtures.…”

“…1,2 In this context, over the last two decades the transition metal polypyridyl complexes have received a considerable amount of attention. [3][4][5][6][7][8][9][10][11][12] In particular coordinatively saturated ruthenium(II) polypyridyl complexes have received much attention because of their tuneable photophysical and photochemical properties, leading to a wide range of successful or potential applications in the field of photochemistry, photo-physics, and biochemistry. 4,5,13,14 A widely studied [Ru(bpy) 3 ] 2+ (bpy = 2,2 0 -bipyridine) complex binds electrostatically to DNA having binding affinity in the order of 10 3 M À1 , 15 but when one of the bpy ligands is replaced with a dppz (dppz = dipyrido[3,2-a:2 0 ,3 0 -c]phenazine) ligand, it results in the [Ru(bpy) 2 (dppz)] 2+ complex that binds intercalatively to DNA with a binding constant of the order 10 6 M À1 and this complex also behaves as a molecular light switch for DNA.…”